CAD consortium scores recommended over DF classification
medwireNews: Differences in US and European guidelines for evaluating the pretest probability of obstructive coronary artery disease (CAD) result in significantly different risk estimations, which may influence further treatment for a significant proportion of individuals evaluated for chest pain, study findings indicate.
The analysis, which included 2274 consecutive patients without prior CAD referred for coronary computed tomography angiography, showed that the Diamond and Forrester (DF) score, recommended by the American College of Cardiology/American Heart Association, significantly overestimated the prevalence of obstructive CAD when compared with the CAD consortium basic and clinical scores, recommended by the European Society of Cardiology (ESC).
Ron Blankstein (Brigham and Women’s Hospital, Boston, Massachusetts, USA) and co-researchers say their findings “support using the CAD consortium clinical score instead of the Diamond and Forrester classification.”
They add: “This change will likely [result] in a reduction in the overall need for additional testing as a larger number of individuals will be appropriately reclassified at a low probability of obstructive CAD.”
Although higher scores were associated with a higher likelihood of CAD for all three models, the DF score demonstrated a poor model fit, which resulted in a significant overestimation of disease prevalence, mainly for individuals with higher scores, that did not occur with the CAD consortium basic or clinical scores.
The DF score was also significantly less capable of discriminating between individuals with and without obstructive CAD, with an area under the receiver operating characteristic curve of 0.713 versus 0.752 and 0.791 for the CAD consortium basic and clinical models, respectively.
This meant that significantly fewer individuals were categorised as low risk, thus requiring no additional testing, with the DF score than with the CAD consortium models, at 8.3% versus 24.6% and 30.0%, respectively.
Conversely, significantly more individuals had a high pre-test probability for CAD with the DF score, at 18.0%, than with the CAD consortium scores, at 1.1% each.
This significant reduction in individuals who, according to guideline recommendations, would subsequently be treated as having presumed CAD and could be referred directly to invasive angiography, “could significantly decrease utilization of testing in a group which is unlikely to have significant disease”, Blankstein et al remark in Circulation.
By Laura Cowen
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